I don't shoot much shot, but I'll throw in my 2 cents on roundball.
For context, I shoot a 54 caliber (28 ga) North Star West trade gun. I typically shoot it at 25 yards, easily groups 2 inches. The gun probably shoots better than I can aim.
The best load for this gun is 65 grains of 3F, an over powder card, .530 ball, and an over shot card to cap it off. No lube, no patch. I can shoot it all day and cleaning is easy.
I've tried a patched roundball, it shoots ok. .520 ball and .010 patch lubed with Wonder Lube. The bore runs a bit tight on this gun.
Have also tried a lubed wad, found it offered nothing over using the over powder cards.
I really wish Matt Denison was still running North Star West, he made a great gun!